Media storage system

ABSTRACT

The system comprises one or more storage devices ( 34 ) for storing data media, particularly CDs, a read/writer ( 50 ), a picking and transfer device ( 42 ), a series of rotary platters ( 22 ) stacked one on top of the other and each associated with a drive device ( 60, 62 ) acting on the periphery of platters to rotate these between a position in which the disks are stored and a position in which the disks can be accessed. Each platter has a slot ( 28 ) and when all the platters ( 22 ) are in the storage position, the slots ( 28 ) define an open channel which allows the transfer device ( 42 ) to move vertically.

The present invention relates to a system for storing data media withautomatic access to each of the data media, comprising at least onestorage device for storing the data media, a read/writer of the datamedia, a picking and transfer device for transferring each data mediumseparately between the storage device and the read/writer, or viceversa, in which each storage device comprises a series of rotary supportplatters stacked one on top of the other which are carried by a verticalcentral column and which can be rotated separately using an appropriatedrive device acting on the periphery of each of the support platters torotate these between a storage position and an access position, in whicheach support platter comprises a series of storage spaces, closed towardthe outside in a horizontal plane, to accommodate the data media, and anopening arranged with the storage spaces in a concentric circle aroundthe central column, the arrangement being such that when all the supportplatters are in their storage position their openings are verticallyaligned one on top of the other to define an open channel.

These systems are used to store large quantities of data, particularlyCDs, in the case of decentralized management of disks where the user andhis workstation are geographically removed from this data storage andmanagement center. In fact it constitutes a disk or video library, withautomatic and random access to each individual disk, that needs to allowa great many remote users or customers to transfer, in a short space oftime and by remote control, a selected CD from its storage space intoone of the numerous pieces of equipment in the read/writer.

One of the criteria measuring the quality of such a system is the speedof access to the CDs and of their transfer to the read/writer. However,the greater the storage capacity of the system, the more problematicthis speed of access becomes.

The IBM Technical Disclosure Bulletin, Vol. 37, No. 5, May 1994, NewYork, US, pages 155-158: “Disk input/output station for rotationcarousel” describes a jukebox consisting of support platters stacked oneon top of the other and able to rotate separately. Each support platterhas, on a concentric circular line, a certain number of storage spacesand a disk opening.

The storage spaces on the platters each have a cut-out alignedvertically and which in the support platter extend radially outward.When the storage spaces and the openings of all the support platters arepositioned one on top of the other, a horizontal disk picker arm canenter the storage spaces and openings from the outside of the supportplatters and move vertically throughout the jukebox.

Given that the platters have to have radial openings, the platter drivedevice needs to be arranged at the center and needs to be movedvertically in order to be able to be engaged with the various platters.This does, however, lead to a loss of time. An additional loss of timeis caused by the design of the disk transfer device. What actuallyhappens is that when a CD is being set in place this CD needs to belifted up above its support platter before this platter can be turnedinto the desired position. Likewise, when extracting a CD, the CD hasfirst of all to be lifted up by the transfer device before the supportplatter can be turned into the correct position for removal from thevertical well.

Document EP 0 722 168 proposes a system of the kind described in thepreamble, the storage capacity and speed of execution of which aremarkedly improved over the system described in the aforesaid document.In document EP 0 722 168, the storage spaces in which the CDs are storedon the support platters are radially closed, allowing the platters to bedriven from their periphery, and making it possible to provide aseparate drive system for each support platter. However, this systemalso gradually reaches the storage capacity limits when its height isincreased. This is because given that the access well is radially closedand that the reader is above the system, the picking and transfer deviceneeds to move vertically through the well which may lengthen the timetaken to access the disks, particularly the bottom disks, when theplatter stack height increases. The picking and transfer system may alsobe subjected to vibrations as the height increases.

The object of the present invention is to provide a storage system ofthe kind described in the preamble with a large storage capacity and ahigh speed of access to the disks.

To achieve this objective, the present invention anticipates a storagesystem that has the characteristics of claim 1. Other particulars andcharacteristics of the invention can be found in the sub-claims.

The storage system proposed by the present invention has all theadvantages offered by the system proposed in document EP 0 722 168.Furthermore, it offers the additional advantage of a higher speed atwhich orders are executed and a practically unlimited heightwise storagecapacity. This is because given that the read/writer lies beside thestorage device(s), the device for picking and transferring the datamedia no longer has to move up to the top of the device in order todeposit a data medium in the read/writer or remove it therefrom.Furthermore, given that, according to one preferred embodiment of theinvention, the read/writer consists of a stack of individualread/writers which can be stacked over the entire height of the system,the picking and transfer device can choose the first read/writer whoseloading bay is empty.

Furthermore, when the storage system extends over a relatively greatheight, it is possible to provide several picking and transfer devicesspread over the entire height of the device, thus further increasing thespeed of execution.

Further advantages and specifics of the invention will become apparentfrom reading about an advantageous embodiment set out hereinbelow by wayof illustration with reference to the attached figures in which:

FIG. 1 depicts a perspective view of a stack of support platters for aCD storage device.

FIG. 2 shows, schematically and in perspective, a storage deviceaccording to the invention.

FIG. 3 schematically shows several devices according to FIG. 2 stackedone on top of the other.

FIG. 4 shows, in greater detail, part of the top of the depiction ofFIG. 3.

FIG. 5 schematically shows a view downwards on a storage device.

FIGS. 6 a and 6 b show a pair of support platters and

FIG. 7 schematically shows the details of a platter drive device.

The detailed description which will follow will make reference, by wayof illustration, to a system for storing CDs. The invention may,however, also be applied to other types of data medium.

FIG. 1 shows a perspective view of a jukebox 20 according to the presentinvention. This jukebox consists of a certain number, in the exampledepicted of thirty-two, circular support platters 22 stacked one on topof the other and provided with a round central opening 24 (see alsoFIGS. 6 a and 6 b). The stack is carried by a central column 26 whichextends axially through the openings 24 of the individual platters.

Each platter 22 comprises a slot 28 with a circular end wall and a widthgreater than the diameter of the CDs. This slot 28 opens in an arc of acircle into the peripheral edge of the platter 22. All the platters 22can rotate individually around the column 26. Assigned to each platter22, in the direction of rotation, is a storage position such that, whenall the platters 22 are in their storage positions, the individual slots28 are aligned axially and form a radially open channel 30 extendingover the entire height of the jukebox. When the platter is rotated, asshown in FIG. 1, away from its storage position, its surface concernedbecomes accessible, through the channel 30, to a picking devicedescribed in greater detail later on.

As can be seen in FIG. 1 and in FIGS. 6 a and 6 b, each platter 22comprises, apart from the central opening 24 and the slot 28, a certainnumber, in the example depicted six, of circular storage spaces 32 fordepositing and storing six CDs. The storage spaces 32 and the circularend wall of the slot are arranged in a ring around the central opening24 so that as the platters 22 rotate, the storage spaces 32 each pass,one after the other, across the channel 30. If the individual platters22 rotate far enough there is therefore freedom to access the individualplatters 22 and each of their storage spaces 32, and the CDs containedtherein. As can be seen from FIGS. 1 and 6, the storage spaces 32 arearranged in two groups, one of four and one of two, spaces 32. Thereason for this arrangement will be explained later on.

The dimensions of the platters 22 and the number of solid spaces 32 oneach platter 22, and the number of platters 32 stacked one on top of theother can be tailored to the individual requirements of each company. Inthe case of 32 platters each having six storage spaces 32, the jukeboxdepicted in FIG. 1 has a capacity of 192 CDs. It is also conceivable toanticipate larger platters 22 having more than six storage spaces 32.

The individual platters may be made of a synthetic substance or ofmetal, preferably of aluminum.

After the manner of document EP 0 722 168, the platters have adinner-plate profile and they are mounted on the central column 26 inexactly the same way as they were in that document. The shape of theplatters and their mounting on the column 26 will not therefore bedescribed in detail in the context of this patent application and thereader should refer to document EP 0 722 168, particularly FIG. 3thereof, for further information on this subject.

FIG. 2 schematically illustrates a storage device 34 comprising ajukebox 20 contained in a casing 36 with a lateral opening providingaccess to the channel 30. The jukebox 20 is associated with a pair ofdrive systems 38, 40 for driving the platters, which extend over theentire height of the jukebox 20 and will be described in greater detaillater on.

FIG. 3 shows that it is possible to stack several storage devices 34 ofFIG. 2 one on top of the other in order thus to form a high-capacitystorage tower. FIG. 3 schematically shows a picking and transfer device42 visible in greater detail in FIG. 4 and which slides along a verticalrail 44 stretching over the entire height of the tower. This verticalmovement can be afforded by any means known per se such as an endlessscrew, a belt, a cable, etc. Depending on the height of the tower it ispossible to provide several picking and transfer devices sliding alongthe rail 44.

Each picking and transfer device 42 comprises a pivoting picking arm 48at the end of which there is a pneumatically operated suction cup orsome other device able to pick and transport a CD. Because of thepivoting movement of the picking arm 48, the slots 28 of the platters 22defining the channel 30 do not run radially in the platters 22 but in anarc of a circle conforming to the radius of pivoting of the suction cup46.

The reference 50 in FIG. 3 schematically denotes the CD read/writer. Theread/writer 50 may consist of common individual read/writers 52,possibly slightly adapted, stacked one on top of the other to form atower facing the rail 44. A reader must be understood to mean a piece ofequipment containing either readers or writers or both, or alternativelyitems of equipment able both to read and to write. As FIG. 4 shows, eachpiece of equipment comprises a retractable bay 54 able to accommodate aCD. When the bay 54 is free, the center of its accommodating area is inthe radius of action of the picking arm 48 and its suction cup 46.

When a remote user wishes to consult a given CD he orders this remotelyand this unlocks the platter 22 bearing this disk from its storageposition in which the slot 28 is aligned with the channel. The platter22 is then rotated in one direction or the other, depending on whichstorage space 32 bears the requested disk, to bring this storage spaceand the disk into the channel 30. During this time, the picking device42 is lowered automatically while the arm 48 pivots in the channel 30into the position of FIG. 4. In close proximity to the requested diskthe picking device is halted while the suction cup 46 is actuated topick up the requested disk. The device 42 is then raised back up alongthe rail 44 as far as the first free read/writer 52. During this time,the platter 22 which has supplied the disk returns to its storageposition to free up the channel 30. At the read/writer 52, the arm 48 ispivoted so that the suction cup 46 can set the disk down in the free bay54 of the read/writer. A disk is returned to its storage platterfollowing the reverse pattern of events.

The various drives and movements are controlled automatically by acentral computer, which means that all the movements are coordinatedwith each other.

The reference 56 in FIG. 3 schematically illustrates a cassette with adisk intended to be set in place or to replace another disk in thestorage device.

This loading or replacement may be performed by hand by an operator whooffers the disk 56 up to the suction cup 46 and commands itssetting-down at a chosen location of the device using the abovescenario.

This operation may also be performed automatically using a tower cabinet58 (FIG. 5) in which the disks to be loaded into the storage device arestacked and which lies facing the channel 30. The picking device 42 canthen automatically find the disks from the cabinet 58 under the controlof an operator.

FIG. 5 shows a view looking down on a storage device in which thetransfer and picking device, depicted in solid line is in the process ofpicking a disk from a platter 22 or of setting it down thereon. Thepivoting range of the picking arm 48 is illustrated by the arrow. Thisarm 48 is also depicted, in broken line, in a position in which it isserving the reader 52 and in a position in which it is serving itselffrom the cabinet 58.

FIG. 5 also shows two devices 60 and 62 for driving the platters 22.Associated with each of the platters 22 is such a device 60 and 62 whichdevices are arranged in two groups over the entire height of the device.This is because, like in document EP 0 722 168, because of the thinnessof the support platters and the very small vertical spacing betweenthem, it is preferable to provide two drive groups, one comprising thedrive motors for the even-numbered support platters and the othercomprising those for the odd-numbered support platters.

As in the storage device known from the aforesaid document, each supportplatter 22 is provided at it periphery with an annulus gear 64 made ofmagnetic soft iron (see also FIGS. 6 a and 6 b) intended to collaboratewith the drive devices 60, 62 with a view to rotating and locking theplatters 22.

However, unlike the storage device in which the annulus gears extendaround the entire periphery of the platters and have no interruption fordrive and locking, the annulus gears 64 of the platters 22 according tothe present invention have necessarily to be interrupted at the slots28, which means that each platter 22 can rotate only to such a pointthat its slot 28 reaches the drive device for the platter concerned. Tosolve the problem, all the drive devices are designed to turn theirplatter 22 in both directions. The consequence is that each platter 22has a space which is lost as a storage space given that this spacecorresponds to the position where the slot would lie virtually facingthe drive device for this plate and that as a result, this space cannotbe rotated into an angular position that blocks off the channel. This iswhy the storage spaces 32 of each platter 22 are grouped in a set offour and a set of two and that there is this dead space between thesetwo groups.

Another consequence is that two types of platter 22 are needed, one forthe drive devices 60 and the other for the drive devices 62. In concreteterms, the platter of FIG. 6 a will be actuated by the drive device 60located to the left in FIG. 5 and the platter of FIG. 6 b will beactuated by the device 62. The drive device 60 will rotate the platter22 of FIG. 6 a in the clockwise direction to bring the group of twostorage spaces 32 into the position of obstructing the channel 30. Bycontrast, in order to bring the group of four storage spaces 32 into aposition of obstructing the channel 30, the platter 22 will be rotatedin the trigonometrical direction. In the case of the platter of FIG. 6b, which is actuated by the drive device 62, the reverse is true.

The devices for driving the platters 22 are similar to those of thedevice known from document E 0 722 168. FIG. 7 shows an advantageousexemplary embodiment of a drive device for rotating the associatedsupport platter about the column 26. The support platter is indicated inFIG. 7 via its peripheral annulus gear 64. Drive is had by apseudo-linear stepping motor known per se. Facing the annulus gear 64there are four magnet armatures 66 which are fixed to a support rail 68extending along the stack of platters. Associated with the two limbs ofeach magnet armature 66 are two adjacent teeth of the annulus gear 64 ofa support platter. Each limb of the four magnet armatures carries awinding 70 which is powered with direct current by an electric circuitknown per se and not depicted. Through sequential cyclic switching ofthe excitation of the windings, each tooth of the annulus gear 64 isattracted by the alternating magnetic field of one magnet limb towardthe other and from one magnet armature 66 to the next, causing theannulus gear 64, to rotate and to thus form the rotor of the steppingmotor. The disks are accelerated and braked also using the steppingmotor.

In order to ensure correct positioning of each support platter 22 in astorage position or in one of the six access positions, i.e. thepositions in which the storage space obstructs the channel 30, a lockingposition is assigned to each storage space 32 and to the slot 28 of eachplatter. For this purpose, a locking device is associated with eachplatter and built into the corresponding drive device.

As FIG. 7 shows, the locking device consists of a soft iron lever 72mounted to pivot on the support rail 68 and the free end of which isprovided with a head 74 in the form of a hollow dish having a shape thatcomplements that of a tooth of the annular gear 64. This lever isassociated with a magnet armature 76 fixed to the support rail 68, thetwo limbs of which armature bear an excitation winding 78 powered withdirect current by an appropriate electric circuit, not depicted. Thelever 72 also experiences the action of a compression spring 80 attachedto the rail 68. When the winding 78 is not excited, the lever 72 ispushed by the spring 80 into a position of engagement with the tooth, asin FIG. 7, i.e. the platter is locked. When the winding is excited, thelever 72 is attracted against the action of the spring and frees theplatter.

The control of the excitation winding 78 is of course synchronized withthe drive device so that each time the driving of a platter is actuated,the platter is automatically unlocked by excitation of the winding 78.

The systems for driving and locking the platters are under the controlof sensors, not shown, sensing the angular positions of the platters.These sensors are advantageously sensors sensitive to the passage andprogress of the individual teeth of the annulus gears 64 past them.

1. A system for storing data media with automatic access to each of thedata media, comprising at least one storage device for storing the datamedia, a read/writer of the data media, a picking and transfer devicefor transferring each data medium separately between the storage deviceand the read/writer, or vice versa, in which each storage devicecomprises a series of rotary support platters stacked one on top of theother which are carried by a vertical column and which can be rotatedseparately using an appropriate drive device acting on the periphery ofeach of the support platters to rotate these between a storage positionand an access position, in which each support platter comprises a seriesof storage spaces, closed toward the outside in a horizontal plane, toaccommodate the data media, and an opening arranged with the storagespaces in a concentric circle around the central column, the arrangementbeing such that when all the support platters are in their storageposition their openings are vertically aligned one on top of the otherto define an open channel in which the openings of the support plattersare slots with a diameter greater than that of the data media and opento the periphery of the platters and in which the drive devices fordriving the platters are designed to cause the platters to rotate inboth directions, characterized in that the read/writer and the pickingand transfer device are situated near the open channel defined by theslots in the platters, in that the read/writer is a unit independent ofthe storage system and comprises a multiplicity of individual readersand/or writers stacked one on top of the other near the picking andtransfer device, and in that the latter is designed to slide along theopen channel defined by the slots.
 2. The storage system as claimed inclaim 1, characterized in that the picking and transfer device comprisesat least one pivoting arm bearing at its free end a picker for pickingthe data media and able to slide along a vertical rail stretching overthe entire height of the storage system.
 3. The storage system asclaimed in claim 1, characterized in that each platter is associatedwith a separate drive device and in that the drive devices are arrangedin two groups one associated with the even-numbered support platters andthe other with the odd-numbered support platters.
 4. The storage systemas claimed in claim 3, characterized in that each drive device consistsof a pseudo-linear stepping motor and in that each support plattercomprises a peripheral annulus gear made of magnetic soft iron formingthe rotor of the stepping motor.
 5. The storage system as claimed inclaim 1, characterized in that each support platter has six circularstorage spaces.
 6. The storage system as claimed in claim 5,characterized in that the six storage spaces of each platter arearranged in two groups, of four and of two, storage spaces which arearranged one group on each side of the slot in their platter and in thatthis platter is turned in a first direction to transfer the storagespaces of the group of four from the storage position to the accessposition and in the opposite direction to transfer the storage spaces ofthe group of two from the storage position to the access position. 7.The storage system as claimed in claim 1, characterized by a lockingdevice for locking in the storage position and in the access position.8. The storage system as claimed in claim 7, characterized in that eachplatter is associated with a locking device consisting of a pivotinglever the free end of which bears a head that can be engaged in a toothof the annulus gear under the action of a spring and from which it isdisengaged under the action of an electromagnet.
 9. The storage systemas claimed in claim 1, characterized in that each storage device iscontained in a casing with a lateral opening giving access to thechannel, and in that the system comprises several storage devicesstacked one on top of the other.